diff --git a/rowers/dataprep.py b/rowers/dataprep.py
index 92c5c37b..d24c549c 100644
--- a/rowers/dataprep.py
+++ b/rowers/dataprep.py
@@ -182,7 +182,11 @@ def clean_df_stats(datadf,workstrokesonly=True,ignorehr=True,
     except KeyError:
         pass
 
-    datadf=datadf.clip(lower=0)
+    try:
+        datadf=datadf.clip(lower=0)
+    except TypeError:
+        pass
+
     datadf.replace(to_replace=0,value=np.nan,inplace=True)